Motor Thermistors; Serial Communication; Grounding; High Voltage Warning - Danfoss VLT DMS 300 Manual

Motor thermistors

If the motor is fitted with thermistors these may
be connected directly to the DMS. To connect the
thermistors, first remove the shorting link, and then
connect the thermistors between terminals 31A & 31B.
Use double-isolated thermistors to
retain PELV.

Serial communication

The DMS can be equipped with either AS-i or
Profibus communication capabilities.
The AS-i and Profibus interfaces are optional.
The AS-i Fieldbus is connected at terminals 125 & 126.
The details of the Profibus connectivity are given
at the end of the manual.
NOTE
Communications and control cabling should
not be located within 1 ft (300 mm) of power
cabling. Where this cannot be avoided
consideration should be given to providing magnetic
shielding to reduce induced common mode voltages,
for example, by laying the communication and
control cables in a separate conduit.

Grounding

Ensure that the DMS unit is grounded
properly. Use the chassis ground studs
provided for the purpose (4 of size M4).
For type T73 units, an external ground plug
(size M8) is provided to facilitate grounding.
To retain the IP rating of DMS, remember
to close all the unutilized cable entries
using the gland plugs (bungs) provided
loose with the DMS unit. In units with external plugs,
all plugs must be correctly mounted.

High voltage warning

The voltage of the DMS is dangerous
whenever the equipment is connected to
the AC line. Ensure the DMS is correctly
connected and that all safety measures have been
taken before switching on the supply.
MG.90.F2.22 - VLT is a registered Danfoss trademark
Decentral Solutions

Galvonic isolation (PELV)

All control terminals, and terminals for serial
communication are safely isolated from the
AC lines potential, i.e. they comply with the
PELV requirements of EN/ IEC 60947-1. PELV isolation
of the control card is guaranteed provided there is
max. 300 VAC between phase and ground.
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